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    <title>Document</title>
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    <script>
        //编写函数getobj(arr) 统计数字出现的次数。


        // getobj(arr){
        //     return obj; { a: 2, b: 2, c: 1 }
        // }
        // var arr = ["a", "a", "b", "c", "b"];
        var obj = {};
        function getobj(arr) {
            for (var i = 0; i < arr.length; i++) {
                // var num = arr[i];
                if (obj[arr[i]]) {
                    obj[arr[i]] += 1
                } else {
                    obj[arr[i]] = 1;
                }
            }
            return obj;
        }
        var arr = [12, 11, 12, 12, 12, 11, 3, 6, 6, 5, 5, 5, 3, 99, 12, 55]
        console.log(getobj(arr));
    </script>
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